Effect of crop stage on blackleg [Leptosphaeria maculans] disease severity and yield of canola in Alberta, Canada. H. U. Ahmed, S. F. Hwang, Q. Zhou, G. D. Turnbull, S. E. Strelkov and G. Peng. Crop Diversification Centre North, Alberta Agriculture and Rural Development, 17 507 Fort Road N.W., Edmonton, AB T5Y 6H3, Canada; (S.E.S.) Department of Agricultural, Food and Nutritional Science, 410 Agriculture/Forestry Centre, University of Alberta, Edmonton, AB T6G 2P5, Canada; and (G.P.) Saskatoon Research Centre, Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N 0X2, Canada
Blackleg of canola (Brassica napus L.), caused by Leptosphaeria maculans (Sowerby) Karst. (anamorph: Phoma lingam (Tode ex. Fr.) Desm.), is a serious disease worldwide causing yield losses of 5–50%. To assess the effect of inoculation and frequency of fungicide application on blackleg severity, stand establishment and seed yield of canola at different growth stages, two field sites were seeded with canola and inoculated with blackleg-infested canola stubble at the cotyledon, five-leaf or flowering stages. Stand establishment was lower when the plants were inoculated at the cotyledon or five-leaf stages. Blackleg severity was greater for inoculated plants compared with the non-inoculated control. Inoculation did not affect plant height, pod production or yield. In a separate trial, Headline (pyraclostrobin) was applied at the seedling stage, at the seedling + early flowering stages, or at the seedling + early flowering + late flowering stages. Plant count was greater and blackleg severity was lower in all plots where fungicide was applied compared with the control. Inoculation did not affect plant height, pods per plant or seed yield. The absence of an effect of inoculation or fungicide application on plant size or seed production likely resulted from the ability of plants to compensate for infection. These studies suggest that the application of fungicides at the early growth stages reduces blackleg severity and increases stand establishment of canola. The experiment will be repeated to confirm the results.
Ability of Pyrenophora teres pathotypes to overcome net blotch resistance in Canadian barley genotypes. A. AKHAVAN, T. K. TURKINGTON, H. ASKARIAN, W. G. LEGGE, A. TEKAUZ, J. R. TUCKER AND S. E. STRELKOV. Department of Agricultural, Food and Nutritional Science, 410 Agriculture/Forestry Centre, University of Alberta, Edmonton, AB T6G 2P5, Canada; (T.K.T.) Lacombe Research Centre, Agriculture and Agri-Food Canada (AAFC); 6000 C & E Trail, Lacombe, AB T4L 1W1, Canada; (W.G.L., J.R.T.) Brandon Research Centre, AAFC, 2701 Grand Valley Road, Brandon, MB R7A 5Y3, Canada; and (A.T.) Cereal Research Centre, AAFC, 195 Dafoe Road, Winnipeg, MB R3T 2M9, Canada
Barley cultivars and lines resistant to net (NFNB) and spot (SFNB) forms of net blotch were evaluated against representative pathotypes of Pyrenophora teres Drechs. f. teres Smedeg. (Ptt) and P. teres Drechs. f. maculata Smedeg. (Ptm) at the seedling stage. Separate experiments were conducted for each form using a completely randomized block design with four replicates. All experiments were repeated. One week following inoculation, the second and third leaves of each plant were rated according to 1–10 and 1–9 disease severity scales for Ptt and Ptm, respectively. Plants with scores of 1–5 and >5, for Ptt, and 1–3 and >3, for Ptm, were scored as resistant and susceptible, respectively. The NFNB resistance in the cultivars ‘Vivar’ and ‘CDC Helgason’ was overcome by two and four of the Ptt isolates, respectively. ‘AAC Synergy’ exhibited resistance against all Ptt pathotypes examined; however, two isolates caused disease severities of almost 5, suggesting some adaptation to the resistance in this cultivar. Among the breeding lines tested for NFNB, TR253, CI9819 and TR236 were the most resistant with average disease severities of almost 3. Resistance to SFNB in ‘CDC Meredith’ was overcome by all pathotypes tested, while ‘AAC Synergy’, ‘Cerveza’ and ‘Major’ were resistant to all of the pathotypes. Among the breeding lines tested for SFNB, TR236 was the most resistant, with an average rating score of almost 4. The identification of pathotypes virulent on cultivars classified as ‘resistant’ indicates the importance of not relying exclusively on resistance as the sole approach to disease management.
Propidium monoazide-assisted PCR may quantify viable Plasmodiophora brassicae resting spores to the exclusion of non-viable resting spores. F. AL-DAOUD, A. DEORA, J. ROBSON, B. D. GOSSEN AND M. R. MCDONALD. Department of Plant Agriculture, University of Guelph, Guelph, 50 Stone Road East, ON N1G 2W1, Canada; (B.D.G.) Saskatoon Research Centre, Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N 0X2, Canada; and (A.D.) Syngenta Canada Inc., 140 Research Lane, Research Park, Guelph, ON N1G4Z3, Canada
Clubroot of canola (Brassica napus L.) caused by Plasmodiophora brassicae Woronin is a major threat to canola production in the Canadian prairies and worldwide. This is partly due to the ability of P. brassicae resting spores to remain viable in soil for years. Quantitative PCR (qPCR) can be used to quantify soil-borne spores, however it amplifies DNA from viable and non-viable spores. Propidium monoazide (PMA) has been used in conjunction with qPCR (PMA-PCR) to prevent amplification of DNA from non-viable microorganisms. PMA is thought to penetrate damaged cells, and intercalate into DNA thereby inhibiting its amplification. The objective of this study was to assess the potential for using PMA-PCR to quantify viable spores of P. brassicae while excluding non-viable spores. Naturally infested muck soil and resting spores isolated from clubbed roots of cabbage (B. oleracea L. var. capitata) were heat treated (80°C for 10 min) to produce a mixture of viable and non-viable spores. Extracted spores were then treated with different PMA concentrations (40–120 µM) followed by qPCR analysis. Heat treatment did not affect spore numbers obtained from qPCR with no PMA. In contrast, PMA-PCR detected a reduction in the number of resting spores after heat treatment: 641-fold (99%) for spores extracted from clubs and five-fold (79%) for spores extracted from soil. This study indicates that PMA-PCR may quantify viable resting spores of P. brassicae while excluding non-viable resting spores. Current research is comparing different manual extraction protocols for use with PMA-PCR, and comparing PMA-PCR with different vital stains.
Can bacterial antagonists be used to complement synthetic fungicides as a control measure against potato late blight? P. AUDY, S. M. BOYETCHKO, N. FORAN AND V. GRAVEL. Soils and Crops Research and Development Centre, Agriculture and Agri-Food Canada, 2560 Hochelaga Boulevard, Quebec, QC G1V 2J3, Canada; (S.B.) Saskatoon Research Centre, Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N 0X2, Canada; and (N.F., V.G.) Department of Plant Science, Macdonald College, McGill University, 21,111 Lakeshore Road, Ste-Anne-De-Bellevue, QC H9X 3V9, Canada
Late blight of potato (Solanum tuberosum L.), caused by Phytophthora infestans (Mont.) de Bary, is the world’s single most economically important food crop disease with crop losses and prevention measures estimated worldwide at more than $6.0 billion annually. Chemical fungicides are heavily used by potato producers to prevent and control the disease but public pressure has created a demand for environmentally friendly control products and a preference for pesticide-free foods are driving the exploration for biological control options. Moreover, incidence of new, more virulent P. infestans isolates and isolates becoming insensitive to existing synthetic fungicides has been challenging for producers to prevent late blight epidemics. The use of biological fungicides has thus been of considerable interest in complementing the arsenal of control measures against potato late blight. The objective of this study is to identify and develop biological alternatives for control of this economically important disease. A potato leaf bioassay was developed to study the ability of the bacteria to control the disease under environmental conditions optimum for disease development. From over 50 bacterial isolates, six leading candidates showed promising abilities to impede P. infestans growth (A1 and A2 mating-type isolates). For each bacterial strain evaluated, four treatments were tested: pathogen alone, whole bacterial culture + pathogen, bacterial filtrate + pathogen and autoclaved bacteria culture + pathogen. All treatments were compared with mock controls (minus pathogen, minus bacteria). Application of whole bacterial culture, and in some cases, bacterial filtrate alone, have resulted in significant reduction in disease severity. The presence of bacterial metabolites possessing antifungal compounds and induced resistance are implicated as possible modes of action. Further testing is required to determine optimum conditions for maximizing bacterial formulation.
Canadian taxa of the Alternaria spp. complex identified by multilocus DNA sequence analysis. T. BARASUBIYE, J. MACK, K. A. SEIFERT, S. PATRICK, K. SIVAGNANAM AND T. GRAFENHAN. Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, ON K1A 0C6, Canada; and (S.P., K.S., T.G.) Grain Research Laboratory, Canadian Grain Commission, 1404-303 Main Street, Winnipeg, MB R3C 3G8, Canada
Species of the genus Alternaria cause a wide range of economically important diseases on a variety of crops and are difficult to identify based on morphology. We report a DNA method based on multilocus (Adenosine triphosphatase (ATPase), Chitinase, Translation elongation factor 1-alpha (EF1-alpha), Endo-polygalacturonase (Endo-PG), Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and RNA polymerase II (RPB2) sequence analysis to characterize and identify Alternaria spp. collected in Canada from different crops. Genomic DNA was extracted from a total of 160 cultures of Alternaria spp. using the Qiagen DNeasy Plant Mini kit. We successfully amplified amplicons of uniform sizes from genomic DNA of all the Alternaria isolates using primers targeting the six selected genes. No amplification was obtained from genomic DNA of large-spored species with primers designed to amplify a portion of Endo-PG gene. With a primer pair designed to amplify EF1-alpha, we consistently obtained an amplicon (330 bp) that discriminates the group with small conidia from the cultures of Alternaria producing large conidia. Using a multilocus DNA sequencing approach, we demonstrated the potential of Endo-PG gene to discriminate Alternaria gaisen Nagano, a quarantine species in the Alternaria alternata (Fr.) Keissler spp. complex. Phylogenetic analysis based on RPB2 sequences, revealed eight lineages within a clade harbouring Alternaria spp. producing small conidia. These results could have practical application in reliable identification of Alternaria spp. in agricultural important crops.
Promising bacterial antagonists as biopesticides for control of post-harvest diseases of fruits and vegetables. S. M. BOYETCHKO, A. M. SVIRCEV, T. ZHOU, P. AUDY, R. K. HYNES AND J.-C. CÔTÉ. Saskatoon Research Centre, Agriculture and Agri-Food Canada (AAFC), 107 Science Place, Saskatoon, SK S7N 0X2, Canada; (A.M.S.) Vineland Research Station, AAFC, 4902 Victoria Avenue North, P.O. Box 6000, Vineland, ON L0R 2E0, Canada; (T.Z.) Guelph Food Research Centre, AAFC, 93 Stone Road West, Guelph, ON N1G 5C9, Canada; (P.A.) Soils and Crops Research and Development Centre, AAFC, 2560 Hochelaga Boulevard Québec, QC G1V 2J3, Canada; and (J.-C.C.) Horticulture Research Development Centre, AAFC, 430 Gouin Boulevard, Saint-Jean-sur-Richelieu, QC J3B 3E6, Canada
Post-harvest and storage diseases, caused by an assortment of fungal pathogens, can lead to approximately 20–25% of losses in fruits and vegetables worldwide. They significantly reduce yield and quality during production and can result in complete loss of market value during storage. Chemical fungicides are the primary means of controlling these diseases, but a major challenge is to reduce the application of synthetic pesticides while extending the shelf life of fruits and vegetables during off-peak season and long distance transportation while maintaining high quality produce. Microbial antagonists used as biopesticides have been investigated extensively for managing these diseases and are a viable option for both the industry and consumer. A 4-year project was initiated to develop biopesticides for Botrytis cinerea (Persoon) Fries, Monilinia fructicola (Winter) Honey, Phytophthora infestans (Mont) de Bary, and Penicillium expansum Link, which cause a variety of post-harvest diseases. In vitro and in vivo bioassays were used to screen several hundred bacterial strains for broad-spectrum activity against these post-harvest pathogens. Impedance tests revealed the presence of bacterial metabolites that inhibit growth of these fungi. In vivo bioassays also demonstrated the inhibitory effects of whole bacterial cultures and/or bacterial filtrate containing bacterial natural products against B. cinerea on tomato; however, application of whole bacterial culture reduced disease severity to a greater extent than bacterial filtrate alone. The formulation of bacteria in carnauba wax as a carrier proved to be a model system to apply bacteria for control of brown rot of apple and will be expanded on other post-harvest pathogens.
Stripe rust disease dynamics in southern Alberta, Saskatchewan, and Manitoba, 2009–2014. G. S. BRAR, B. D. MCCALLUM, D. A. GAUDET, B. J. PUCHALSKI, M. R. FERNANDEZ AND H. R. KUTCHER. Crop Development Centre, Department of Plant Sciences, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada; (B.D.M.) Cereal Research Centre, Agriculture and Agri-Food Canada (AAFC), 101 Route 100, Unit 100, Morden, MB R6M 1Y5, Canada; (D.A.G., B.J.P.) Lethbridge Research Centre, AAFC, 5403 1 Avenue South, Lethbridge, AB Canada T1J 4P4, Canada; and (M.R.F.) Semiarid Prairie Agricultural Research Centre, AAFC, 1 Airport Road, P.O. Box 1030, Swift Current, SK R6M 1Y5, Canada
Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici West. is an important disease of wheat worldwide. Stripe rust was initially limited to the irrigated areas of southern Alberta, but has been frequently observed in Saskatchewan, Manitoba and most of Alberta since 2000. In 2009 and 2010, stripe rust was widespread in eastern Saskatchewan but severity was low. In 2010, stripe rust was severe in southern Alberta on the susceptible cultivars ‘AC Bellatrix’, ‘CDC Abound’ and ‘Superb’, but only trace to low levels were observed on the resistant cultivars ‘Harvest’, ‘CDC Go’ and ‘Lillian’. Severe symptoms developed on seedling resistance gene Yr10 (carried by ‘AC Radiant’) for the first time. In 2011, stripe rust was epidemic in southern Alberta and Saskatchewan. High moisture created favourable crop canopy conditions in spring wheat and prevented timely fungicide application, which resulted in high levels of secondary inoculum. In 2012, stripe rust occurrence and severity were low, but many growers made unwarranted fungicide applications based on the epidemic in 2011. In 2013, stripe rust was widespread but severity was generally low to moderate in Saskatchewan and Alberta. In 2014, stripe rust occurred at trace or low levels in south-western Saskatchewan, but was severe on susceptible cultivars in southern Alberta. Stripe rust occurred at trace to low levels in Manitoba in each year except 2011, where it was prevalent and severe early in the season. These surveys indicate that stripe rust occurs regularly on susceptible wheat cultivars across western Canada, but prevalence and severity vary greatly among regions and years.
Fusarium head blight resistance QTLs Fhb1, Fhb2, and Fhb3 reduce disease severity by up to 50% in near-isogenic wheat lines developed by marker-assisted selection. G. S. BRAR, C. J. POZNIAK, Y. RUAN, J. THOMAS, H. R. KUTCHER AND P. J. HUCL. Crop Development Centre, Department of Plant Sciences, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada; (Y.R.) Semiarid Prairie Agricultural Research Centre-Agriculture and Agri-Food Canada, 1 Airport Road, P.O. Box 1030, Swift Current, SK R6M 1Y5, Canada; and (J.T.) 87, Pulberry Street, Winnipeg, MB R2M 2C4, Canada
Fusarium head blight (FHB) is caused by various Fusarium spp., particularly F. graminearum Schwabe, F. avenaceum (Fr.) Sacc., and F. poae (Peck) Wollenw., and is the most serious disease affecting wheat (Triticum aestivum L. and T. turgidum L.) across Canada. Quantitative trait loci (QTLs) associated with FHB resistance can be validated by quantifying their effects when in a common background such as in near-isogenic lines (NILs). Two single seed descent NIL populations were developed from the crosses CDC Go (susceptible)×4/04GC0139 (resistant) and CDC Alsask (susceptible)×4/04GC0137 (resistant). The near-isogenic line populations were developed by backcrossing F1 plants to CDC Go or CDC Alsask. At the BC4F1 generation, each NIL was screened by microsatellite (SSR) markers associated with Fhb1, Fhb2 and Fhb3. Approximately 1,900 BC2F1 and 1,200 BC3F1 hybrid seeds were genotyped. The three major QTLs were successfully backcrossed to CDC Go and CDC Alsask with the recovery of all eight possible combinations. The FHB resistant QTL derived from ‘Sumai 3ʹ, and then introgressed into CDC Go and CDC Alsask, reduced the severity of infection in greenhouse trials by up to 50% and 25%, respectively. In an inoculated field nursery, the FHB visual rating index was halved in lines carrying all three QTLs (Fhb1+Fhb2+Fhb3), relative to the recurrent parent (CDC Go). The results suggest that marker-assisted selection (MAS) to stack Fhb1, Fhb2 and Fhb3 QTLs is effective in improving FHB resistance relative to the susceptible recurrent wheat parent.
2014 Survey for Fusarium graminearum 15-ADON, 3-ADON and NIV chemotypes and mycotoxins level in winter wheat in Ontario. P. BURLAKOTI AND L. TAMBURIC-ILINCIC. University of Guelph, Ridgetown Campus, 120 Main Street East, Ridgetown, ON N0P 2C0, Canada
Fusarium head blight (FHB) caused by Fusarium graminearum Schwabe (FG) is a serious disease of wheat (Triticum aestivum L.). Deoxynivalenol (DON) is the mycotoxin most commonly detected in contaminated wheat grain in Ontario, Canada. Grain samples from six winter wheat cultivars included in the ‘2014 Ontario Performance Trial’ planted at Ottawa, Palmerston and Ridgetown were selected at harvest to assess the percentage of Fusarium-infected kernels (FIK), the percentage of FG (identified as per cent of total Fusarium spp.) and the frequency of FG chemotypes (15-ADON, 3-ADON and Nivalenol-NIV). The cultivars were: ‘25R40ʹ and ‘Wentworth’ (highly susceptible to FHB), ‘Emmit’ and ‘Princeton’ (moderately susceptible) and ‘Ava’ and ‘AC Morley’ (moderately resistant). One hundred and fifty kernels of each cultivar per location were surface-sterilized in 0.16% NaOCl (dilute commercial bleach) for 3 min, air dried, and plated on acidified potato dextrose agar. The kernels were incubated for 7 days under a 12:12 hour light:dark cycle at room temperature. Subsequently, single spore cultures of FG were recovered and identified morphologically. Genomic DNA was extracted from 48 single spore isolates of FG per location (total of 144). The FG isolates were also identified using molecular markers specific to FG. 15-ADON, 3-ADON and NIV chemotypes of the fungal strains were identified using TRI3- and TRI-12 based molecular markers. In addition, the grain was sampled to determine deoxynivalenol (DON), 15-acetyl DON, 3-acetyl DON, nivalenol (NIV), T-2 and HT-2 toxins using a LC‐MS/MS system. The highest average percentage of FIK was found in ‘Princeton’ (41.3%), ‘25R40ʹ (29.3%) and ‘Wentworth’ (44.0%) in Ottawa, Palmerston and Ridgetown, respectively. The highest percentage of FG was observed in ‘25R40ʹ in Ottawa (83.3%) and Palmerston (90.9%), and ‘Princeton’ in Ridgetown (94.6%). Per cent of FG 15-ADON chemotype was 63.9%, 95.8% and 97.9% from Ottawa, Palmerston and Ridgetown, respectively. 2.1% of NIV was detected at Palmerston and Ridgetown, and NIV was not detected in Ottawa. 3-ADON was detected at 36.1% in Ottawa, only 2.1% at Palmerston and was not detected at Ridgetown. DON level was low in general in 2014, and the highest in ‘Wentworth’ at Ridgetown (1.6 µg g−1). Accumulation of other mycotoxins was below detection limit. We concluded that the frequency of the FG 3-ADON chemotype in winter wheat in Ottawa was much higher in 2014 (36.1%) than recorded previously (2–7%) from anywhere in Ontario.
Differentiation of Plasmodiophora brassicae populations and single-spore isolates using CAPS markers. T. CAO, S. F. HWANG AND S. E. STRELKOV. Department of Agricultural, Food and Nutritional Science, 410 Agriculture/Forestry Centre, University of Alberta, Edmonton, AB T6G 2P5, Canada; and (S.F.H.) Crop Diversification Centre North, Alberta Agriculture and Rural Development, 17507 Fort Road, Edmonton, AB T5Y 6H3, Canada
The soilborne parasite Plasmodiophora brassicae Woronin causes clubroot, an important disease of crucifers. Physiological specialization exists in populations of P. brassicae, and pathotype 3 (as defined on the differentials of Williams) is predominant on canola (Brassica napus L.) in Alberta, Canada. However, a novel strain of the pathogen, pathotype 5x, has been recently identified in this region. Unlike pathotype 3, pathotype 5x is virulent on all clubroot resistant canola cultivars available in Canada. The objective of this study was to develop cleaved amplified polymorphic sequence (CAPS) markers to distinguish pathotypes 3, 5x and a collection of other P. brassicae isolates and populations representing pathotypes 2, 5, 6 and 8. A total of 24 single-spore isolates and seven populations were included in the analysis. The P. brassicae-specific primers PbsF1 and PbsR1, designed based on a small subunit ribosomal RNA gene sequence from the pathogen, amplified a major polymerase chain reaction (PCR) product 2120 bp or 1746 bp in size from P. brassicae-infected roots. Digestion of the amplicon with PvuII yielded a characteristic fragment of 1438 bp in size from tissues infected with P. brassicae isolates representing pathotype 6, whereas a 1064 bp band was obtained from isolates representing pathotypes 2, 3, 5 and 8. In populations of the novel pathotype 5x, the primers amplified two major and distinctive fragments about 2000 bp and 3000 bp in size. Digestion of these amplicons with PvuII also yielded distinctive banding patterns. These CAPS markers have good potential as tools to distinguish pathotypes of P. brassicae.
First report of Phytophthora causing root rot in soybean in Alberta, Canada. K. F. CHANG, S. F. HWANG, H. U. Ahmed, Q. ZHOU, H. FU, S. E. STRELKOV, R. L. CONNER, D. L. MCLAREN, M. W. HARDING AND G. D. TURNBULL. Crop Diversification Centre (CDC) North, Alberta Agriculture and Rural Development (AARD), 17507 Fort Road, Edmonton, AB T5Y 6H3, Canada; (S.E.S.) Department of Agricultural, Food and Nutritional Science, 410 Agriculture/Forestry Centre, University of Alberta, Edmonton, AB T6G 2P5, Canada; (M.W.H.) CDC south, AARD, 301 Horticultural Station Road East, Brooks, AB T1R 1E6, Canada; (R.L.C.) Morden Research Station, Agriculture and Agri-Food Canada (AAFC), Unit 100-11, Route 100, Morden, MB R6M 1Y5, Canada; and (D.L.M.) Brandon Research Centre, AAFC, 2701 Grand Valley Road, Brandon, MB R7A 5Y3, Canada
Soybean (Glycine max (L.) Merr.) has great potential as a crop in western Canada. However, root rot is a common constraint on soybean production, and occurred in all 29 soybean fields that were surveyed in southern Alberta in 2014. Phytophthora spp. cause seed rot, pre- and post-emergence damping off, stem and root rot wherever soybean is produced, but it has not been previously reported in association with soybean in Alberta. This study examined the presence of Phytophthora spp. on soybean roots collected in southern Alberta. Following a survey of soybean fields in 2014, plants with typical root rot symptoms were plated onto a selective medium (modified PBNIC agar), and 20 isolates were tentatively identified as Phytophthora spp. based on their colony characteristics. Among these, three isolates were homothallic, producing smooth, thick-walled oospores and mostly paragynous with some amphigynous antheridia on lima bean agar. Based on these criteria, the three isolates were identified as Phytophthora sojae Kaufmann & Gerdemann. The identity of the isolates will be confirmed by molecular analysis, and their pathogenicity will be assessed on a collection of soybean genotypes. This is the first report of Phytophthora spp. causing root rot in soybean in Alberta.
Variation for virulence of Saskatchewan Septoria triseti isolates on genotypes of canary seed. L. P. CHOLANGO-MARTINEZ, P. HUCL AND H. R. KUTCHER. University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada
An understanding of virulence within pathogen populations is important for the development of durable disease resistance in crops. Leaf mottle caused by Septoria triseti Speg., is the most common disease of canary seed (Phalaris canariensis) in Saskatchewan. To date, there has been little genetic characterization of this pathogen. The objective of this project was to identify variation for virulence in the S. triseti population from Saskatchewan on 24 canary seed genotypes under controlled environmental conditions. A total of 14 isolates of S. triseti were collected during 2007 and 2013. At the three leaf stage, seedlings were inoculated with a conidial suspension of each isolate in replicated experiments. At 10 days after inoculation, leaf mottle infection type was recorded using a 0–5 scale; 0 denoting no symptoms and 5 being highly susceptible as defined by large lesions with profuse pynidia production. Infection types of ≤2 were classified as a resistant reaction and >2 as susceptible. Eleven pathotypes were identified among the 14 isolates evaluated: four isolates were identical and 10 unique. Among the 24 canary seed genotypes, there were two and seven genotypes that had identical reactions to S. triseti. The differential interactions observed between pathogen isolates and host plant genotypes suggest gene-for-gene interactions.
Decline in the concentration of resting spores of Plasmodiophora brassicae and the effect of crop rotation following a susceptible crop. J. A. DALTON, B. D. GOSSEN, F. AL-DAOUD, D. PAGEAU AND M. R. MCDONALD. Department of Plant Agriculture, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada; (B.D.G.) Saskatoon Research Centre, Agriculture and Agri-Food Canada (AAFC), 107 Science Place, Saskatoon, SK S7N 0X2, Canada; and (D.P.) AAFC, 1468 St-Cyrille Street, Normandin, QC G8M 4K3, Canada
The concentration of resting spores of Plasmodiophora brassicae Woronin in soil increases rapidly when susceptible crops are grown in short rotation. Some of these spores survive for many years, but the rate of decline is unknown. There may be a practical advantage to a 2- to 3-year break between susceptible canola (Brassica napus L.) and a clubroot-resistant cultivar. The objective of this research was to determine the concentration of resting spores following different durations of crop rotation including susceptible canola. Small blocks in a naturally infested field at Normandin, Québec, have been in cropping rotations that included clubroot-susceptible canola in rotation with barley, field pea and fallow treatments. Resting spore populations in soil were quantified after continuous canola and break intervals of 1, 2, 3, 5 and 6 years between canola crops, using a multiplex qPCR protocol. The concentration of resting spores in soil declined over time as the length of break from the susceptible canola crop increased. Regression analysis indicated a quadratic relationship of y = 1E + 07e−0.759x . R2 = 0.65. Compared with continuous canola (1.3 × 108 spores g−1 soil), resting spore concentration declined by 96% after a 1-year break, 99% after a 2-year break, but then declined very slowly after a 3-, 5- and 6-year break (<1%). These results support a previous report. In general, large numbers of resting spores die or disappear in the first 2 years after a susceptible crop, then remain at a relatively constant, low concentration following longer rotations out of canola.
Effect of spore load on growth of clubroot-resistant canola. J. A. DALTON, B. D. GOSSEN AND M. R. MCDONALD. Department of Plant Agriculture, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada; and (B.D.G.) Saskatoon Research Centre, Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N 0X2, Canada
Clubroot caused by Plasmodiophora brassicae Woronin reduces yield in canola (Brassica napus L.). Genetic resistance is essential for clubroot management. However, studies indicate that high spore loads may reduce growth and delay development in clubroot-resistant canola cultivars. The objective of this research was to compare the growth response of clubroot-resistant canola to P. brassicae resting spore load in soil. In 2014, clubroot-resistant and susceptible canola was planted at two adjacent sites at the Muck Crops Research Station (Holland Marsh, Ontario) with the same soil type and agronomic practices, but differing in spore loads of P. brassicae. Plant height was measured weekly from 4–8 weeks after planting. Clubroot incidence and severity were assessed using a standard 0–3 rating scale. Severe clubroot (100 DSI) developed in susceptible canola at both sites. Resistant cultivars had no clubroot symptoms. At 8 weeks after planting, at Site 1 (7 × 105 spores g−1 soil), plant height of resistant cultivars was 124% (±4.5) greater than the susceptible control. The proportion of resistant cultivars at flowering or pod development stage was 30% (±3.2) greater than the susceptible control. At 8 weeks after planting, at Site 2 (7 × 106 spores g−1 soil), plant height of resistant canola was 46% (± 3.9) greater than the susceptible control. The proportion of resistant cultivars at flowering or pod development stage was 20% (±2.8) greater than the susceptible control. These field results support the observations from controlled environment trials that high concentrations of resting spores of P. brassicae cause reduced growth and delayed development of clubroot-resistant canola.
Evaluation of Syngenta and competitor seed treatments for control of seed-borne cereal pathogens. A. DEORA, E. PERSSON, M. VAN ANDEL, H. WRIGHT AND T. LABUN. Syngenta Canada Inc., 140, Research Lane, Research Park, Guelph, ON N1G 4Z3, Canada
This study evaluated the effect of seed treatments for suppression of seed-borne pathogens on naturally infested wheat seeds in a plate test and on seed germination in a blotter paper assay. Canada Prairie Spring cultivars, ‘Hanley’ and ‘Pasteur’, were tested with the following seed treatments: Vibrance® Quattro, a premix of difenoconazole, sedaxane, fludioxonil and metalaxyl-M, and Vibrance XL plus Proseed®, a premix of difenoconazole, sedaxane and metalaxyl-M combined with fludioxinil (Syngenta Canada Inc.), Insure® Cereal (pyraclostrobin, triticonazole and metalaxyl) (BASF Canada Inc.), Raxil® Pro (tebuconazole, prothioconazole and metalaxyl) (Bayer CropScience Inc.), Rancona® Apex (ipconazole) and Vitaflo® (carbathiin and thiram) (Chemtura Canada Co.). Vibrance Quattro and Vibrance XL plus Proseed seed treatments had less total pathogen incidence (%) and area of colonization (%) on both cultivars relative to untreated controls and other treatments. Also, the Syngenta seed treatments had better suppression of Fusarium graminearum Schwabe (teleomorph Gibberella zeae (Schwein.) Petch) and Alternaria sp. on ‘Hanley’ and Alternaria sp. on ‘Pasteur’ compared with other seed treatments. Incidence of Aspergillus sp., Cladosporium sp., Epicoccum sp., other Fusarium spp. and Penicillum sp. were also assessed. Germination was higher in all seed treatments compared with untreated control in ‘Hanley’; only Vibrance Quattro and Vibrance XL plus Proseed had higher germination than the untreated control in ‘Pasteur’. All of the treatments were equally effective for germination in both cultivars. Syngenta’s seed treatments improved germination of infested wheat seeds over untreated seeds, and suppressed total incidence and area of colonization of seed-borne pathogens better than competitor seed treatments.
Process of transferring fusarium head blight resistance from Thinopyrum elongatum to spring wheat. G. FEDAK, D. WOLFE, D. T. CHI, W. CAO AND A. G. XUE. Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, ON K1A 0C6, Canada
Germplasm with fusarium head blight (FHB) resistance will normally contain a number of major resistance QTL plus a number of minor QTL – all spread over the entire genome. It was thus unusual to find an aneuploid containing a single chromosome (7E) introgressed from Thinopyrum elongatum (2x) to have a high level of FHB resistance (9.6% infected florets following inoculation, compared with the parental cultivar at 57.5%). The Ph1b mutant is being used to induce chromosome pairing and recombination between 7E and a wheat chromosome, and thus transfer the resistance. The Ph1b mutant was crossed and backcrossed once to the three substitution lines 7E (7A), 7E (7B) and 7E (7D), giving 556 BC1 seeds. These seeds were screened with marker PSR574, specific for Ph1b, and 43% of the backcross progeny were found to be homozygous recessive for Ph1b. The plants that were homozygous recessive for Ph1b were inoculated with Fusarium graminearum Schwabe and meiosis studied in them. Progeny from resistant plants that showed complete chromosome pairing at meiosis are being evaluated with chromosome 7E-specific markers to identify plants with the smallest 7E introgressions, following mapping, the resistance QTL will be used to enhance FHB resistance in wheat breeding programmes.
Genomic perspective of variation in Phytophthora ramorum virulence. C. HAMMETT, S. F. SHAMOUN AND R. C. HAMELIN. University of British Columbia Forest Sciences and Conservation, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada; (S.F.S.) Pacific Forestry Centre, Natural Resources Canada, 506 West Burnside Road, Victoria, BC V8Z 1M5, Canada; and (R.H.) Laurentian Forestry Centre, Natural Resources Canada, 1055 Rue du Peps, Quebec, QC G1V 4C7, Canada
Phytophthora ramorum Werres et al., the causative agent of sudden oak death in North America, is an invasive species that is responsible for killing oak trees in California and Oregon and causes Ramorum blight in over 100 species of plants. There are four clonal lineages that have been identified thus far: NA1, NA2, EU1 and EU2. The NA1 lineage has the largest geographic distribution and was the first lineage discovered in North America and has been extensively studied. The discovery of NA1 isolates with phenotypes that include irregular colony edges, low sporulation, and decreased pathogenicity in planta, known as ‘non wild-type’, has provided targets for comparisons between phenotypes and genotypes. A collection of 23 NA1 isolates, as well as three isolates from each of the other three lineages were characterized for growth rate, mycelial density, low sporulation, and lesion size on detached leaves of rhododendron leaves (Rhododendron caucasicum × ponticum ‘Cunningham’s white’), camelia (Camellia japonica ‘Pink Diddy’), and arbutus (Arbutus menziesii). The data were used to characterize the variation in the NA1 lineage non wild-type isolates. Eight NA1 isolates, four wild-type and four non wild-type, were chosen for genome sequencing and transcriptome analysis using next-generation sequencing. Genomes were aligned to the reference sequence and will be used to identify mutations in pathogenicity-associated genes and polymorphisms correlated with the phenotype data. The expression profiles were compared between wild-types and non wild-types to discover genes associated with virulence in the phenotypes in vitro and in planta.
Genetic diversity and necrotrophic effectors in the barley pathogen Rhynchosporium commune in Alberta, Canada. M. D. Holtz, J. Zantinge, K. Xi and T. K. Turkington. Field Crop Development Centre, Alberta Agriculture and Rural Development, 6000 C & E Trail, Lacombe, AB T4L 1W1, Canada; and (T.K.T.) Lacombe Research Centre, Agriculture and Agri-Food Canada, 6000 C & E Trail, Lacombe, AB T4L 1W1, Canada
Scald is an important foliar disease of barley, caused by the fungus Rhynchosporium commune Zaffarano et al. (formerly R. secalis (Oudem.) J.J. Davis). Little is known about the molecular population biology of the species within Canada. The presence of necrotrophic effectors (NEs) and the genetic diversity was determined for 230 R. commune isolates collected from barley in central Alberta. The genes for the three known NEs in the species, NIP1, NIP2 and NIP3, were present in almost all isolates studied. Genetic diversity was examined using eight simple sequence repeat (SSR) markers. Thirty-six alleles were detected, three to eight per locus. The clonal fraction among the isolates was 39%, with clones commonly being found at the same location. Linkage disequilibrium between loci was found to be insignificant. The presence of a large clonal fraction, but insignificant linkage disequilibrium indicates the species likely has a mixed reproductive system. There was little differentiation between populations. After clone correction only a small (10%) but significant differentiation (Φpt = 0.095, P = 0.001) could be detected between populations. No alleles were confined to a specific population. Moreover, cluster analysis using shared allele distances between isolates showed no differentiation between regions within central Alberta.
Effect of fungicide application on the management of pasmo in flax. T. ISLAM, C. VERA, J. SLASKI, R. MOHR, K. RASHID AND H. R. KUTCHER. Department of Plant Sciences, Crop Development Centre, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada; (C.V.) Melfort Research Centre, Agriculture and Agri-Food Canada (AAFC), P.O. Box 1240, Melfort, SK S0E 1A0, Canada; (J.S.) Alberta Innovates, P.O. Box 4000, Vegreville, AB T9C 1T4, Canada; (R.M.) Brandon Research Centre, AAFC, 2701 Grand Valley Road, Brandon, MB R7A 5Y3, Canada; and (K.R.) Morden Research Centre, AAFC, Unit 100-101, Route 100, Morden, MB R6M 1Y5, Canada
Pasmo disease of flax, caused by Septoria linicola (Speg.) Garassini, is commonly observed in western Canada every year. It reduces both the quality and quantity of flax, and when severe, seed yield may be reduced by as much as 60–70%. The main objectives of this study were to determine the impact of fungicide and application timing on pasmo in flax in terms of seed yield and quality at Brandon, MB; Melfort, SK; Saskatoon, SK; and Vegreville, AB in 2014. Two fungicides, pyraclostrobin (100 g a.i. ha−1) and fluxapyroxad (50 g a.i. ha−1), were applied to flax as single applications and in combination (100 g a.i. pyraclostrobin ha−1 and 50 g a.i. fluxapyroxad ha−1) at mid-flower, late flower and at both stages. The combination of both fungicides was the most effective to reduce disease severity especially at Brandon and Saskatoon. Pasmo did not occur at Vegreville. The timing of fungicide application did not impact pasmo severity at any of the sites and the results from a single application were similar to those from the two applications. Fungicide application improved the seed yield over the check at Saskatoon only; no significant difference was observed among the treatments at the other sites. At Saskatoon, the combination of fungicides increased the seed yield up to 59% as compared with the check, followed by fluxapyroxad (40%) and pyraclostrobin (28%), however, these products also delayed crop maturity. Thousand seed weight, test weight and oil content were also improved the most by the combination of fungicides.
Wheat germplasm development by gene pyramiding for resistance to Ug99. X. JIN, D. T. CHI, B. ZHANG, A. G. XUE, W. CAO AND G. FEDAK. Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, ON K1A 0C6, Canada
Most of the current stem rust resistance genes (Sr) in Canadian wheat varieties are ineffective against the Puccinia graminis f. sp. tritici Pers./Eris. & Henn. Ug99 races which pose a major threat to wheat production worldwide. Several stem rust resistance genes, including Sr33, Sr35, Sr36, SrCad/Sr42 and Sr43, are effective against the Ug99 race TTKSK. Although Sr36 became ineffective against the Ug99 race TTTSK, it is still potentially useful for pyramiding these genes to develop durable stem rust resistant germplasm. For this purpose, we made two crosses among RL5405 (Sr33), RL6099 (Sr35), Lang (Sr36), AC Cadillac (SrCad/Sr42) and RWG34 (Sr43) which contain the corresponding Sr genes. A total of 54 doubled haploid (DH) lines were produced from F1 hybrids involving (AC Cadillac/Lang)//(RWG34/RL5405) and 82 DH lines obtained from RWG34/RL5405//RL6099. Twelve genotypes with different Sr gene combinations including Sr33+Sr36+SrCad/Sr42+Sr43, Sr33+Sr36+SrCad/Sr42, Sr33+Sr36+Sr43, Sr33+SrCad/Sr42+Sr43, Sr36+SrCad/Sr42+Sr43, Sr35+Sr33+Sr43, Sr33+Sr36, Sr33+Sr43, Sr36+SrCad/Sr42, Sr36+Sr43, Sr35+Sr33, Sr35+Sr43 were verified by linked PCR markers. Another population with 63 DH lines was derived from the combination (Hoffman*2/RL6099)//(Hoffman*2/Lang) which was made to improve Hoffman’s resistance to Ug99. Seventeen of 63 DH lines contained both Sr35 and Sr36 genes, indicating that the combination of Sr35+Sr36 was pyramided in the Canadian wheat cv. ‘Hoffman’ and these lines may be used for development of resistant cultivars to Ug99 in Canada.
Identification of effective sources of resistance to cereal cyst nematode in wheat germplasm from Canada and the USA. H. J. LI, S. F. HWANG, K. F. CHANG; R. L. CONNER AND S. E. STRELKOV. Institute of Crop Science, Chinese Academy of Agricultural Science, Beijing 100081, China; (S.F.H., K.F.C.) Crop Diversification Centre North, Alberta Agriculture and Rural Development, 17 507 Fort Road N.W., Edmonton, AB T5Y 6H3, Canada; (R.L.C.) Morden Research Station, Agriculture and Agri-Food Canada, Unit 100-101, Route 100, Morden, MB R6M 1Y5, Canada; and (S.E.S.) Department of Agricultural, Food and Nutritional Science, 410 Agriculture/Forestry Centre, University of Alberta, Edmonton, AB T6G 2P5, Canada
Cereal cyst nematode (CCN, Heterodera avenae and H. filipjevi) is an increasingly important pathogen that threatens wheat production in China. The lack of effective resistance sources has limited breeding efforts for managing CCN. Field tests were carried out in Xingyang (H. avenae) and Xuchang (H. filipjevi) to examine the reactions to CCN of over 100 genotypes of common wheat and durum wheat cultivars, as well as wheat-tall wheatgrass (Thinopyrum ponticum) partial amphiploids. The durum cultivars ‘Wascana’ and ‘Wacooma’ from Canada, ‘Madsen’, a common wheat cultivar from Washington, USA, and the wheat-tall wheatgrass partial amphiploids SS485 and SS498 were highly resistant to both species of Heterodera, as shown by the small number of white females that developed on their roots. Histological examination revealed that fewer nematode juveniles were able to penetrate the roots compared with the susceptible genotypes, which indicates that a mechanism exists to prevent penetration by the nematode juveniles. Inoculation tests demonstrated that these common wheat and durum wheat cultivars were resistant to CCN pathotypes from different wheat-producing regions. The transfer of the CCN resistance to local wheat cultivars has resulted in the identification of a large number of breeding lines with resistance to CCN. Recombinant inbred line (RIL) populations have been developed for mapping the QTLs for CCN resistance. Since the majority of commercial wheat cultivars currently used in most regions are highly susceptible to CCN, these newly identified sources of resistance to local CCN pathotypes offer an opportunity to improve CCN resistance in China.
Transcriptome profiling reveals whitebark pine (Pinus albicaulis Engelm.) genetic diversity for resistance to white pine blister rust. J.-J. Liu, R. A. Sniezko, M. Murray, N. Wang, R. N. Sturrock, A. Zamany, A. Kegley AND D. Savin. Pacific Forestry Centre, Canadian Forest Service, Natural Resources Canada, 506 West Burnside Road, Victoria, BC V8Z 1M5, Canada; (R.A.S., A.K., D.S.) USDA Forest Service, Dorena Genetic Resource Center, 34963 Shoreview Road, Cottage Grove, Oregon, 97424, USA; (M.M.) Ministry of Forests, Lands and Natural Resource Operations, #401-333 Victoria Street, Nelson, BC V1L 4K3, Canada; and (N.W.) Academy of Agriculture and Forestry Science, Qinghai University, 253 Ningda Road, Xining, Qinghai, 810016, China
Whitebark pine (WBP, Pinus albicaulis) is one of the pioneer species and has many ecological benefits in high-elevation forests in North America. This wide-ranging species provides valuable contributions to watershed protection, wildlife habitat, food source for several species. WBP stands are, however, vulnerable to several environmental disturbances, including white pine blister rust (WPBR) caused by exotic fungus Cronartium ribicola Fischer, mountain pine beetle, fire suppression and climate change. WPBR has killed about 50% of WBP trees in the Rocky Mountains, up to 85–95% of the stands in some high pathogen hazard areas since its arrival in the early 20th century. As a result, WBP is listed as endangered by the Committee on the Status of Endangered Wildlife in Canada and has been designated ‘warranted, but precluded’ in the USA under the Endangered Species Act. Therefore, disease resistance screening programmes have been undertaken in Canada and the USA to determine the frequency and levels of resistance and their potential utility for conservation and restoration of this endangered species. No major gene has as yet been identified, but families differing remarkably in resistance have been identified in artificial inoculation trials. The resistance appears to have a number of components, notably resistant families showing a lower percentage of seedlings with stem infections, latent stem infections, bark reactions and ability to tolerate or survive longer with stem infections. In general, less than 1% of all whitebark pines are rust resistant. Traditional breeding may benefit from advanced genomic technologies and novel marker-assisted selection approaches. In the present genomics study, genetic variations in terms of resistance to WPBR were investigated by RNA-seq-based transcriptome profiling and high-throughput genotyping of single nucleotide polymorphisms (SNPs). A collection of WBP germplasm from British Columbia was used for construction of cDNA libraries in RNA-seq analysis. Approximately one billion 2 × 100-bp reads were obtained from vegetative organs (needles, stems and roots) of 2-year-old seedlings and de-novo assembly generated the WBP transcriptome containing >300,000 unique transcripts. Bioinformatic SNP detection identified >100,000 high quality SNPs among BC seed-families. To find SNP markers useful for WBP breeding conservation, 120 seed-families collected across western North America were genotyped. The latest analysis results on association of SNP markers with quantitative disease resistance will be presented and application of WBP SNP markers will be discussed. The WBP transcriptome database and those validated SNP markers provide novel genomic resources for genetic, evolutionary and ecological studies.
Fungicide application at anthesis provides effective leaf spot control in spring wheat. D. E. MACLEAN, W. MAY, G. PENG, K COLES, T. K. TURKINGTON, M. HARDING AND H. R. KUTCHER. University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada; (W.M.) Indian Head Research Farm, Agriculture and Agri-Food Canada (AAFC), P.O. Box 760, Indian Head, SK SOG 2K0, Canada; (G.P.) Saskatoon Research Centre, AAFC, 107 Science Place, Saskatoon, SK S7-N 0X2, Canada; (K.C.) Farming Smarter, #100 5401-1st Avenue South, Lethbridge, AB T1J 4V6, Canada; (T.K.T.) Lacombe Research Centre, AAFC, 6000 C & E Trail, Lacombe, AB T4L 1W1, Canada; and (M.H.) Crop Diversification Centre South, Agriculture and Rural Development, 301 Horticultural Station Road East, Brooks, AB T1R 1E6, Canada
Leaf spotting diseases commonly occur in spring wheat causing yield losses of up to 15%, depending on cultivar and environmental conditions. Recently, fusarium head blight (FHB) has become a major concern as yield losses may be >50%, and the pathogen produces mycotoxins. Optimal fungicide timing to control leaf spots is at the flag leaf stage and for FHB at anthesis. The objective of the current study was to determine whether applying fungicide at anthesis would provide adequate control of leaf spots compared with application at flag leaf. Five fungicide mixtures were applied to cv. Carberry at two timings: flag leaf or anthesis, and both. The experiment was conducted at 10 locations over 2 years. Results were analysed by: (1) brown soil zone with low disease severity; (2) black soil zone with low disease severity; and (3) black soil zone with high disease severity. There was no difference in yield when applying fungicide at flag leaf or anthesis in either black or brown soil zones with low disease severity. In the black soil zone with high disease severity, there was a greater reduction in leaf spot severity when fungicide was applied at flag leaf stage or at both timings than at the anthesis stage. However, yield was higher when fungicide was applied at anthesis compared with flag leaf stage, and greater with applications at both timings than a single application at either timing. These results suggest the optimum timing of fungicide application for maximum yield is at anthesis of wheat.
Pathogenicity of Pythium spp. to soybean and resistance in a Canadian short-season cultivar set. G. MARCHAND, C. GIORGETTI, M. YAN, E. R. COBER AND A. G. XUE. Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, ON K1A 0C6, Canada
Pythium Pringsh. spp. cause seed root, seedling damping-off and root rot of numerous crops worldwide. In Canada, this pathogen hinders the establishment of soybean (Glycine max (L.) Merr.) crops in the cool, wet conditions often prevalent in the spring. The objectives of this work were to characterize the pathogenicity of Pythium isolates from soybean fields and evaluate resistance to highly pathogenic species within a set of short-season soybean cultivars and breeding lines. The pathogenicity of a collection of 99 Pythium isolates from soybean fields in Ontario was initially investigated using an in vitro seed rot assay, followed by an in vivo seedling damping-off assay in the greenhouse. Pathogenicity as measured by the inhibition of seed germination was species-dependent, with P.ultimum var. ultimum Trow and P. ultimum var. sporangiiferum Drechsler demonstrating higher pathogenicity than other species. A set of 92 Canadian short-season soybean cultivars or breeder lines was screened for partial resistance to two isolates of P. ultimum var. ultimum using the seedling damping-off assay. Most cultivars showed high (50% or greater) or moderate (25–49%) seedling mortality, on average of the two isolates and compared with the untreated control. A subset of cultivars showing less than 25% of seedling mortality was identified and these cultivars constitute a source of resistance to improve future short-season soybean cultivars and study the mechanisms of resistance to this pathogen.
Opportunities for use of fumigation/solarization to manage clubroot in Canada. J. ROBSON, B. D. GOSSEN AND M. R. MCDONALD. Department of Plant Agriculture, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada; and (B.D.G.) Saskatoon Research Centre, Agriculture and Agri-Food Canada, 107 Science Place Saskatoon, SK S7N 0X2, Canada
Clubroot [Plasmodiophora brassicae Woronin] is an important disease of Brassica crops worldwide. Lab and field trials were conducted in 2014 to assess the efficacy of the fumigants metam-sodium and chloropicrin against resting spores of P. brassicae in soil and the potential for interaction with solarization. Efficacy was assessed using a plant bioassay of clubroot severity on Shanghai pak choi and a vital stain (Evan’s blue) to assess resting spore viability. In a controlled environment study, two formulations of metam-sodium (Busan 1236 and Vapam HL) both virtually eliminated symptoms while the control showed substantial infection (70 DSI). In a field trial on a soil with a high organic content, chloropicrin at 128 kg a.i. ha−1 substantially reduced severity relative to the control (46 vs. 89 DSI) but metam-sodium at 150 and 300 kg a.i. ha−1 was not effective. Within this trial, plots with chloropicrin were covered with an impermeable plastic film, but metam-sodium treatments were not. In a field trial on mineral soil where disease pressure was low, each rate of metam-sodium and chloropicrin assessed eliminated symptoms. In a trial with mineral soil in bins, a 6-week-long solarization pre-planting treatment increased severity relative to the control. This result was unexpected, and may be an artifact unrelated to treatments. Spore viability was not closely associated with treatment efficacy. The high effectiveness of metam-sodium under controlled conditions relative to the field indicated that effective sealing of the soil may greatly improve the effectiveness of fumigant treatments.
Role of storage conditions in seed transmission of yellow mosaic disease in mung bean (Vigna radiata). G. S. SANDHA, A. SIRARI, A. SHARMA AND A. VANDENBERG. Crop Development Centre, Department of Plant Sciences, University of Saskatchewan, Saskatoon, SK S7N 5A8 Canada; and (A.S., A.S.) Department of Plant Breeding & Genetics, Punjab Agricultural University, Ludhiana, Punjab, India
Mung bean (Vigna radiata L.) is an important food legume in the tropical and subtropical parts of world. Among its numerous abiotic stresses, Yellow mosaic disease (YMD) is one of the most devastating diseases. YMD affects the pods of susceptible genotypes resulting in small sized seeds and lower yield. The objective was to determine if YMD in mung bean was transmitted through seeds. Mature pods of mung bean variety RMG 353 (susceptible check) were harvested and stored at ambient temperature till next cropping season. The seeds were sown under whitefly proof net cages and in the open in next season. The caged plants and field grown plants were regularly monitored for symptoms. YMD was observed on plants sown in the open after 45–50 days from sowing. Plants sown under controlled condition did not develop symptoms. The green pods and mature pods showing YMD symptoms were collected to detect the virus through rolling circular amplification (RCA) and polymerase chain reaction (PCR). The virus was detected in green pods with YMD symptoms. The seeds from the mature diseased pods were kept under two storage conditions, one at room temperature and the other at 4ºC. The seeds kept at room temperature and 4ºC were monitored for the presence of TMD virus at monthly intervals. The virus was detected in seeds for up to 1 month for storage at room temperature for up to 2 months of storage at 4ºC. The results suggested that seed does not play a role in YMD transmission but storage conditions and duration can.
Development of species-specific PCR primers and molecular diagnostic assay for the identification and differentiation of North American Heterobasidion spp. S. F. SHAMOUN, C. HAMMETT AND X. LI. Natural Resources Canada, Canadian Forest Service, Pacific Forestry Centre, 506 West Burnside Road, Victoria, BC V8Z 1M5, Canada, and (X.L.) Canadian Food Inspection Agency, 93 Mount Edward Road, Charlottetown, PEI C1A 5T1, Canada
Heterobasidion annosum sensu lato is a species complex of pathogenic white-rot wood decay fungi which cause root and butt rot in conifer stands across the northern hemisphere. The disease is characterized by circles of dead trees that are difficult to diagnose early and remove from infected sites. There are two species in North America: H. irregulare Otrosina & Garbel. and H. occidentale Otrosina & Garbel. While these species were generally differentiated through location and host there has been confusion due to overlapping distribution in the west, shared hosts such as Abies, Larix and Thuja spp., and newly discovered hybrids. Accurate identification is important for phytosanitary reasons as each species has different virulence capacity and host range and could be especially damaging to new countries where host defence is not established. Recently we designed two sets of primers that bind specifically to conserved alleles in glyceraldehyde 3-phosphate dehydrogenase and translation elongation factor 1α genes for H. irregulare and H. occidentale, respectively. These primers were able to quickly and effectively differentiate between the two species from fruiting bodies and infected wood. For the effectiveness of these primers to diagnose infection on suspected stands, we tested these primers, as well as novel Taqman primers for specific and accurate detection of Heterobasidion. These primers are designed to identify trace amounts of Heterobasidion DNA from infected roots and wood of asymptomatic trees in an effort to manage infected sites. Recent focus is on disease management in western red cedar Thuja plicata wood products due to its high economic value to British Columbia.
Pest and diseases of hops in Ontario, Canada, in 2014. F. SHI, M. Filotas, C. Bakker AND M. R. McDonald. Department of Plant Agriculture, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada; and (M.F.) Ontario Ministry of Agriculture, Food and Rural Affairs, 1283 Blueline Road, Simcoe, ON N3Y 4N5, Canada
Hops (Humulus lupulus L.) are an essential ingredient that provides bitterness and aroma unique to beer. Various insects and plant pathogens can reduce yield and quality. Because hops are a re-emerging crop in Ontario, baseline data on pest species and dynamics under eastern North American growing conditions are required to support the continued growth of this industry and develop IPM strategies specific to Ontario. From May to August 2014, two commercial hop yards and one replicated hop cultivar trial at the Simcoe Research Station in Ontario, Canada were scouted weekly for insects and diseases. Potato leafhoppers (Empoasca fabae Harris), Japanese beetles (Popillia japonica Newman) and two-spotted spider mites (Tetranychus urticae Koch) were the most common insect pests found. Cultivars ‘Bertwell’, ‘Galena’, ‘Zeus’, ‘Chinook’ and ‘Centennial’ showed both significantly lower number of potato leafhoppers and less severity of hopperburn. The least feeding damage by Japanese beetle was observed on ‘Chinook’. No differences in two-spotted spider mite counts were seen among cultivars. Downy mildew, caused by Pseudoperonospora humuli (Miyabe &Takah.) G.W. Wilson was observed at all sites. Although no cone damage was observed at harvest due to downy mildew, infected basal spikes and shoots were observed during the growing season. In 2014, symptoms of Alternaria cone disorder, caused by Alternaria alternata (Fr.) Keissl. were observed at the commercial hop yards and on all 10 cultivars at the Simcoe Research Station. ‘Cascade’ and ‘Bertwell’ showed significantly lower disease severity compared with the other cultivars, whereas ‘Hallertauer’ showed the highest.
The occurrence of blackleg in relation to the Avr-allele profile of Leptosphaeria maculans in commercial canola fields in western Canada. W. M. SOOMRO, H. R. KUTCHER AND G. PENG. Saskatoon Research Centre, Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N 0X2, Canada; and (H.R.K.) Department of Plant Sciences, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada
In western Canada, blackleg [Leptosphaeria maculans (Desmaz.) Ces. & de Not] of canola (Brassica napus L.) has increased in both prevalence and severity in recent years, possibly due to a shift in the pathogen population and erosion of cultivar resistance. The objective of this study was to assess the relationship between ‘resistance erosion’ observed in commercial canola fields in 2012 and 2013 and the absence of particular avirulence (Avr) alleles in the pathogen population. Analysis of 350 isolates from 10 canola fields on a host differential set (12 lines) carrying known R genes showed that the alleles AvrLm1, AvrLm3, AvrLm9 and AvrLep2 were at very low or undetectable levels in these fields, while AvrLm2, AvrLm4, AvrLm6 and AvrLm7 were generally common. This indicates that the specific R genes Rlm1 and Rlm3, common in Canadian canola cultivars, have likely been defeated. Variation in Avr frequency was observed depending on the cultivar, field and region studied, but these differences seemed insufficient to explain the variation in blackleg severity observed in these fields. Subsequent studies showed that despite carrying no effective major R genes, many Canadian cultivars remain resistant to blackleg by limiting the spread of infection into the stem via petioles of infected cotyledons or by restricting rapid disease development in the stem. It appears that the absence of particular Avr alleles in the pathogen population is only one of the factors that contributes to blackleg severity in a given canola field in western Canada.
Aerobiology and epidemiology of Cercospora beticola in Southwestern Ontario. S. L. TEDFORD, R. BURLAKOTI AND C. L. TRUEMAN. Department of Plant Agriculture, University of Guelph, Ridgetown Campus, 120 Main Street West, Ridgetown, ON N0P2C0, Canada; and (R.B.) Weather Innovations Consulting LP, 7159 Queens Line, Chatham, ON N7M5T1, Canada
Cercopora leaf spot (CLS) is the most detrimental disease of sugarbeet in temperate climates. Adding spore activity information to the BEETcast™ advisory tool may optimize disease risk estimates and fungicide application timing. Airborne Cercospora beticola Sacc. spore levels were monitored in 6-hour blocks from April–October 2014, using Burkard volumetric spore traps in Pain Court (PC) and Ridgetown (RT), Ontario sugarbeet fields. Weather data were collected in real-time at each location. Cercospora beticola spores were first detected on 2 May in RT and 11 June in PC, and daily totals peaked on 20 September (RT = 1204; PC = 1433). CLS severity reached 60% in RT and 16% in PC by harvest. Relative humidity was correlated with spore activity (P ≤ 0.001) at both locations 0, 6 and 12 hours before spore capture (r = 0.1234–0.3253). Leaf wetness duration was correlated with spore activity (P ≤ 0.001) at both locations 6 and 12 hours before spore capture (r = 0.1484–0.2980). Temperature was correlated with spore activity (P ≤ 0.001) at all times in RT (r = 0.2290–0.3785). In PC temperature was correlated with spore activity (P = 0.0115) at 0 hour (r = 0.0974). Rainfall was not correlated with spore activity at either location at any time. Results suggest that relative humidity, leaf wetness duration and temperature may be important predictors of spore activity that could be further incorporated into the BEETcast™ advisory tool. Further analysis is underway to better understand relationships among weather variables, spore concentration and CLS.
Strawberry decline disease in New Brunswick, Canada. M. T. TESFAENDRIAS, R. ALLEN, C. MAUND AND R. J. A. TREMBLAY. New Brunswick Department of Agriculture, Aquaculture and Fisheries, P.O. Box 6000, Fredericton, NB E3B 5H1, Canada
Strawberry decline disease (SDD) is caused by a combination of two or more viruses infecting the strawberry (Fragaria x ananassa Duchesne) plant resulting in reduction of yield and fruit quality. In 2013, the New Brunswick Department of Agriculture, Aquaculture and Fisheries detected the presence of two strawberry viruses, strawberry mild yellow edge virus (SMYEV), strawberry mottle virus (SMoV) and the strawberry aphid (Chaetosiphon fragaefolii (Cockerell)) which transmits these viruses, in New Brunswick (NB). The detection and identification of viruses was done with sets of primers for five viruses, using reverse transcription-PCR. A more extensive survey was conducted in 2014 to determine the extent and degree of virus-related SDD on NB farms. Strawberry leaf samples were collected and tested for SMoV, SMYEV, strawberry vein banding virus (SVBV), strawberry crinkle virus (SCV) and strawberry pallidosis associated virus (SPaV). Of the 36 first-year fruiting fields (2013 plantings) surveyed in June and July, multiple strawberry viruses were identified in samples from 34 fields. Of the 16 newly planted fields (2014 plantings) surveyed in October, multiple viruses were detected in samples from nine fields. In both first-year fruiting fields and newly planted fields, the most common virus complex identified was SMYEV and SMoV. Wild strawberry (Fragaria vesca L.) samples collected from six sites had relatively low levels of virus inoculum. Only one of the 72 samples tested positive for multiple viruses. Survey results were used to develop best management practices for SDD management in New Brunswick.
Acibenzolar-S-methyl and uniconazole effects on bacterial spot and bacterial speck and processing tomato yield. C. L. TRUEMAN, S. A. LOEWEN AND P. H. GOODWIN. Ridgetown Campus, University of Guelph, 120 Main Street East, Ridgetown, ON N0P 2C0, Canada; and (P.H.G.) School of Environmental Sciences, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
Tomato field trials were conducted 2011–2013 in Ridgetown, Ontario, Canada, to evaluate foliar applications of the plant defence activator acibenzolar-S-methyl (ASM; Actigard®) and growth regulator uniconazole (UNI; Sumagic®) for management of bacterial speck [Pseudomonas syringae pv. tomato (Okabe) Youing et al.] and spot [Xanthomonas gardneri (ex Sutic) Jones et al.]. UNI applied once at the two-leaf stage (pre-transplanting) was compared with six ASM applications beginning with approximately 6-week-old, six-leaf stage plants (post-transplanting), UNI+ASM and a non-treated control on ‘TSH4ʹ. Early season area under the disease progress curve (ES-AUDPC) was 31–65% lower in all years, and 42 and 50% lower in 2012 and 2013 for ASM and ASM+UNI versus the control. UNI and ASM increased red fruit yield by 21–27% in 2011 and 2013. UNI applied once pre-transplanting, three ASM applications pre-transplanting and UNI+ASM was also compared with three applications of copper hydroxide (CuOH; Kocide 2000®) pre-transplanting, CuOH+UNI, and a non-treated control in ‘TSH4’ and ‘H9909’. ASM+UNI reduced ES-AUDPC by 51–57% versus the control and treatments including CuOH for ‘TSH4’ in 2012. ASM suppressed defoliation by 23% in ‘TSH4ʹ but increased defoliation by 13% in ‘H9909’ compared with the control in 2012. ASM and ASM+UNI increased red fruit yield for ‘TSH4ʹ by 29% versus the control and CuOH+UNI, but it reduced total yield by 24% versus the control, CuOH, and CuOH+UNI in ‘H9909’ in 2012. UNI (pre-transplanting) and ASM (post-transplanting) may be beneficial for disease management and yield in some environments, but ASM (pre-transplanting) can have positive or negative effects depending upon the environment and host genotype.
Application of various oriental mustard – allyl isothiocyanate compounds to suppress soybean cyst nematodes in Ontario. T. Welacky. Greenhouse and Processing Crops Research Centre, Agriculture and Agri-Food Canada, 2585 County Road 20, Harrow, ON N0R 1G0, Canada
Oriental mustard (OM) seed is grown in western Canada and is processed in several areas of the country primarily for confectionary spice products. Products of OM seed processing are mustard oil, ground mustard flour and bran. OM by-products of oil, bran and seed coats contain various forms of allyl isothiocyanate (AITC) that may range in concentrations of 0.01–2%. Several OM materials such as pelleted formulations and ground bran composed of ground seed coat, crushed seed and residual oils were tested on 1.25 m−3 field micro-plots infested with Soybean Cyst Nematodes (SCN) Heterodera glycines from 2008–11. Micro-plots were established in 1994 in a field of Harrow Fox sandy loam, cultured with fallow, corn, soybean rotations with the occasional non-host crop to develop moderate-high populations of SCN cysts and eggs. In 2008 various rates of pelleted OM were applied, incorporated and watered as required to create good dissolving conditions for the material. In 2009–2011, OM ground bran was incorporated and plots were watered either with irrigation or natural rainfall to dissolve the material. The 2008 pelleted material contained a range of 1–1.5%, 2009 ground bran had 0.2–0.9% AITC and 2010–11 ground bran contained double the AITC concentration as compared with the 2009 bran. Soybeans resistant to SCN were planted in a uniform spaced pattern each year. Plant measurements were taken as required. Micro-plots were soil sampled for SCN cysts prior to OM application, mid-season and late autumn. Cysts and eggs were extracted and processed for counting. Across the 4 years of micro-plot trials, results indicated considerable variation between types of OM materials, applied rates and concentrations of AITC. In general, SCN egg populations were not consistently suppressed by the Oriental Mustard products. Details of the impact of OM products and concentrations on SCN populations will be presented.
Effect of ACM941 biofungicide on prevention and control of fusarium head blight in wheat. A. G. XUE, Y. H. CHEN, H. D. VOLDENG, G. FEDAK, T. LÄNGLE AND J. X. ZHANG. Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada (AAFC), 960 Carling Avenue, Ottawa, ON K1A 0C6, Canada; and (T.L., J.X.Z.) Pest Management Centre, AAFC, Ottawa, ON K1A 0C6, Canada
Fusarium head blight (FHB), caused by Fusarium graminearum Schwabe (teleomorph Gibberella zeae (Schwein.) Petch), is a destructive disease of wheat in Canada. A novel fungal strain of Clonostachys rosea (Link:Fr.) Schroers et al., ACM941, was evaluated in a series of greenhouse experiments and field trials for the biocontrol of FHB of wheat in Canada. The research demonstrated that at concentrations above 106 cfu mL–1, ACM941 provided consistent and significant effects, with disease suppression generally equivalent to that achieved with the fungicide tebuconazole when applied as a foliar spray. Effects were most pronounced in combination with moderately resistant cultivars. When applied to crop residues, ACM941 was equally or more effective than the fungicide at reducing the production of perithecia, fruiting bodies of G. zeae that form in crop residues and produce ascospores, which are the initial source of inoculum and responsible for generating epidemics in Canada. The impact was achieved whether it was applied before or after the substrate was infected with the pathogen, and when applied either in autumn or spring in field trials. ACM941 was similarly effective in reducing inoculum levels in maize and soybean residues as well, indicating that it could be applied effectively to residues of preceding crops in a rotation to provide pre-planting protection of a wheat crop. ACM941 may be used as an additional measure for an integrated FHB management strategy and as an effective alternative to the chemical fungicides.
Races of Phytophthora sojae in Ontario, Canada, 2010–2012. A. G. XUE, G. MARCHAND, Y. CHEN, S. Z. ZHANG, E. R. COBER AND A. TENUTA. Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, ON K1A 0C6, Canada; (S.Z.Z.) Soybean Research Institute, Northeast Agricultural University, Harbin, 150030, P. R. China; and (A.T.) Ontario Ministry of Agriculture and Food, P.O. Box 400, Ridgetown, ON N0P 2C0, Canada
Phytophthora root rot (PRR), caused by the oomycete Phytophthora sojae Kaufm. & Gerd., is a devastating disease of soybean worldwide, and has been present in Canada since the 1950s. Major resistance to P. sojae Rps genes have been deployed by soybean breeders to mitigate yield losses, which has caused shifts in the pathogen population to more complex pathotypes and the emergence of new races. This study reports on a survey of races and pathotypes of P. sojae throughout 203 commercial soybean fields and two PRR nurseries in the province of Ontario, Canada, and is the first Canadian extensive survey since the late 1980s. A total of 22 races and one intermediate reaction type (IRT) were detected from 262 isolates from commercial soybean fields. Race 25 was the predominant race, comprising 43 isolates and representing 16% of the pathogen population, and races 3, 4, 5, 6, 7, 9, 28 and 45 were frequently detected, each of these races representing 5–11% of the pathogen population. A total of 16 races and two IRTs were detected in 96 isolates from the two PRR nurseries. Race 3 was the most abundant, representing 23% of isolates, and races 5, 6, 7, 8, 9, 14, 25 and 28 each represented between 5 and 10% of isolates. New races and more complex pathotypes have emerged since the last survey, and this will have implications for the future deployment of Rps genes or other forms of resistance to P. sojae.
Pyramiding genes for resistance to stem rust, leaf rust and fusarium head blight. B. ZHANG, D. T. CHI, C. HIEBERT, T. FETCH, A. G. XUE, W. CAO AND G. FEDAK. Eastern Cereal and Oilseed Research Centre, Agriculture and Agri-Food Canada (AAFC), 960 Carling Avenue, Ottawa, ON K1A 0C6, Canada; and (C.H., T.F.) Morden Research Station, AAFC, Unit 100-101, Route 100, Morden, MB R6M 1Y5, Canada
A screening of spring wheat germplasm in Eastern Canada revealed no resistance to the Ug99 races of stem rust. Leaf rust is a recurring problem in eastern Canada, but is not currently being addressed. Fusarium head blight (FHB) is a recurring problem in all classes of wheat. It is a well-known fact that a single gene for resistance to a disease may not have an effectual lifespan as three genes. This project involved the pyramiding of several stem rust resistance genes with the leaf rust resistance gene Lr34 and FHB resistance gene Fhb1. A total of 68 doubled haploid lines were produced from the hybrid: AC Cadillac (SrCad/Sr42, Lr34)/Carberry (Lr34, Fhb1) // RL5405 (Sr33)/Carberry (Lr34, Fhb1). Sixteen different combinations of the disease resistance genes Lr34, Sr33, SrCad/Sr42 and Fhb1 were recovered. In addition, it is known that gene Bt10 for loose smut resistance is closely linked to SrCad/Sr42. Therefore any genotype with SrCad/Sr42 will also carry Bt10. Consequently some genotypes recovered in this study will contain Lr34, Sr33, SrCad/Sr42, Bt10 and Fhb1. The Ug99 resistance genes Sr39 and SrCad/Sr42 have been added to the cultivars ‘Carberry’, ‘Fusion’, ‘Hoffman’, ‘Scotia’ and ‘FL62R1ʹ that are moderately resistant to FHB. In this way, enhanced germplasm has been produced with Ug99 resistance in a background of moderate resistance to both leaf rust and FHB.
Genetic diversity and aggressiveness of Fusarium spp. isolated from soybean in Alberta, Canada. Q. ZHOU, K. F. CHANG, S. F. HWANG, S. E. STRELKOV, R. L. CONNER, D. L. MCLAREN, Y. YANG, M. W. HARDING AND G. D. TURNBULL. Crop Diversification Centre (CDC) North, Alberta Agriculture and Rural Development (AARD), 17 507 Fort Road N.W., Edmonton, AB T5Y 6H3, Canada; (S.E.S., Y.Y.) Department of Agricultural, Food and Nutritional Science, 410 Agriculture/Forestry Centre, University of Alberta, Edmonton, AB T6G 2P5, Canada; (R.L.C.) Morden Research Station, Agriculture and Agri-Food Canada (AAFC), Unit 100-101, Route 100, Morden, MB R6M 1Y5, Canada; (D.L.M.) Brandon Research Centre, AAFC, 2701 Grand Valley Road, Brandon, MB R7A 5Y3, Canada; and(M.W.H.) CDC South, AARD, 301 Horticultural Station Road East, Brooks, AB T1R 1E6, Canada
Soybean (Glycine max (L.) Merr.) has great potential as an alternative crop to canola in southern Alberta farming systems. However, soybeans are susceptible to Fusarium root rot, which usually results in plant mortality in mid to late summer, and causes severe yield reductions in the crop. A total of 102 isolates identified as Fusarium spp. were recovered from diseased soybean root samples collected from central and southern Alberta from 2011 to 2013. Ten species of Fusarium were identified, with F. acuminatum Ellis & Everh. as the predominant species (32 of 102 isolates), followed by F. equiseti (Corda) Sacc. (17 isolates), F. culmorum Sacc. (14 isolates), F. avenaceum (Fr.) Sacc. (11 isolates), F. oxysporum Schlecht. emend Snyder & Hans (nine isolates), F. redolens Wollenw. (eight isolates), F. torulosum (Berk. & Curtis) Gruyter & Schneid. (five isolates), F. tricinctum (Corda) Sacc. (three isolates), F. commune Skovgaard et al. (two isolates) and F. proliferatum (Matsushima) Nirenberg (one isolate). This is the first report of F. commune causing root rot in soybean in Canada. Phylogenetic analyses based on the translation elongation factor 1-α (EF-1α) and the internal transcribed spacer (ITS) sequence data were used to evaluate genetic diversity, and also used for Fusarium spp. identification in combination with morphological characters. Greenhouse pathogenicity tests showed that all of the isolates were pathogenic on soybean.